A robotic transfer sand casting process

Abstract

The application relates to a robot-translated sand mold casting process and belongs to the technical field of intelligent casting, and comprises the following steps: S1, 3D printing sand mold design: according to three-dimensional data of a casting product, each sand mold model in a sand mold assembly is designed; S2, sand mixing: original sand and regenerated sand are mixed according to a preset proportion to form mixed sand material; S3, printing the sand mold by using a 3D printing device: by adopting a binder jetting technology, each sand mold is printed layer by layer by using the mixed sand material; S4, sand mold treatment: a refractory coating is coated on the surface of the sand mold and is baked and solidified; S5, mold assembly: the sand mold assembly is combined according to an assembly sequence; S6, surrounding box pressure iron; S7, pouring forming. The application prints and forms the sand mold assembly by using the 3D sand mold printing technology, ensures high-precision forming of a complex cavity structure and improves the sand mold manufacturing efficiency. In addition, by mixing and applying the regenerated sand and the original sand, the consumption of the original sand is reduced, the casting solid waste emission is reduced and the development trend of green intelligent casting is met.

Description

Technical Field

[0001] This application relates to the technical field of intelligent casting, and in particular to a sand casting process using a robotic rotary table. Background Technology

[0002] The robot rotary table is a core load-bearing component of an industrial robot, located at the connection between the body and the base, and bears the responsibility for transmitting the rotational torque and dynamic load of the entire machine. Internally, it typically features precision oil passages and bearing mounting surfaces. Structurally, it combines a thick-walled load-bearing area with thin-walled heat dissipation fins, making it a typical complex thin-walled box-type casting. Traditional casting processes for manufacturing robot rotary tables involve hand-molding with furan resin sand, requiring the creation of a dedicated wooden mold for each individual sand mold, which is then assembled using parting lines to form the cavity.

[0003] Regarding the aforementioned technical solutions, the inventors believe that the robot rotary table, as a precision component, comprises multiple independent parts, each requiring a dedicated wooden mold for sand casting. This results in a large number of molds and a lengthy production cycle. Consequently, production costs are increased, and production efficiency is low. Especially in the context of intelligent manufacturing development, traditional processes are insufficient to meet the requirements of intelligent casting islands for complex structural forming and efficient resource utilization. Summary of the Invention

[0004] To reduce the need for molds and improve production efficiency, this application provides a sand casting process for a robot rotary table.

[0005] This application provides a sand casting process for a robot rotary table, employing the following technical solution: A sand casting process for a robot rotary table includes the following steps: S1, 3D printing sand mold design: Based on the three-dimensional data of the casting product, design the sand mold model of each sand mold component; S2. Sand mixing: Mix raw sand and recycled sand in a preset ratio to form mixed sand material; S3. Printing sand molds using 3D printing equipment: Using binder jetting technology, each sand mold is printed layer by layer using mixed sand material; S4. Sand mold treatment: Coat the surface of the sand mold with refractory coating and bake to cure; S5. Assembly: Assemble the sand mold components according to the assembly sequence; S6. Placing a pressure iron around the sand mold: Fill the outside of the sand mold with resin sand, and place a pressure iron on top of the sand mold after curing; S7, casting.

[0006] Optionally, in step S2, the recycled sand is prepared by a sand recycling device, which includes a sand mold crusher, a screening machine and a pyrolysis furnace arranged in sequence.

[0007] Optionally, the pyrolysis furnace is a horizontal pyrolysis furnace, which includes a cracking zone, an oxidation zone, and a sintering zone arranged sequentially with progressively increasing temperatures.

[0008] Optionally, the sand recycling equipment may also include an air classifier located after the pyrolysis furnace.

[0009] Optionally, the screening machine includes a screening shell and a first screen and a second screen disposed inside the screening shell, wherein the first screen is disposed above the second screen, and the mesh number of the first screen is smaller than that of the second screen. The top of the screening machine housing is provided with a feed inlet for receiving crushed sand. A first discharge outlet, a second discharge outlet and a third discharge outlet are provided on one side of the screening housing from top to bottom. The first discharge outlet is located at the end of the first screen, the second discharge outlet is located at the end of the second screen, and the third discharge outlet is located at the bottom of the screening housing.

[0010] Optionally, the air outlet of the air classifier is connected to a cyclone separator, the air outlet of the cyclone separator is provided with a first air duct, the end of the first air duct away from the air classifier is provided with a bag filter, the air outlet of the bag filter is connected to a second air duct, the air outlet of the second air duct extends into the screening housing and is located between the first screen and the second screen.

[0011] Optionally, in step S1, the sand mold assembly includes eight sand molds, namely: sand mold 1#, sand mold 2#, sand mold 3#, sand mold 4#, sand mold 5#, sand mold 6#, sand mold 7# and sand mold 8#. The outer wall of sand mold #1 is provided with several mounting holes that penetrate into the mold cavity. The mounting holes are used to install the first chill. A stop and limiting edge is provided at one end of the mounting hole near the mold cavity. The stop and limiting edge extends radially along the mounting hole and covers part of the mounting hole. When the first chill is inserted into the mounting hole from the outside of sand mold #1, its end face abuts against the stop limiting edge, thereby achieving axial positioning of the first chill. Meanwhile, the area not covered by the stop limiting edge exposes the first chill to the cavity, forming a direct contact surface with the molten metal to ensure quenching efficiency.

[0012] Optionally, the outer side of sand mold #6 is provided with a plug for sealing the remaining space outside the mounting hole.

[0013] Optionally, in step S4, after baking, a filter sheet is placed in the flow channel of sand mold #7.

[0014] Optionally, in step S5, firstly, sand mold #2 is attached to sand mold #1, and sand mold #3 is attached to sand mold #2, and then secured with bolts; secondly, sand mold #4 is pushed to sand mold #1 and secured with bolts; finally, sand mold #5, sand mold #6, sand mold #7 and sand mold #8 are inserted in sequence to complete the mold sealing and secure with bolts.

[0015] In summary, this application includes at least one of the following beneficial technical effects: 1. This application uses 3D sand printing technology to print sand mold components for robot rotary tables. Compared with the traditional wooden mold split molding process, it completely eliminates the mold manufacturing process, ensures high-precision molding of complex cavity structures, and greatly improves the efficiency of sand mold production. In addition, by using recycled sand and original sand in combination, it significantly reduces the consumption of original sand and reduces the emission of foundry solid waste.

[0016] 2. By setting up sand recycling equipment, the waste sand molds are mechanically disintegrated using a sand mold crusher, transforming the blocky sand molds into renewable granular raw materials. The crushed sand is then classified by particle size using a screening machine, accurately selecting sand particles of the target particle size. The screened sand particles are then subjected to high-temperature treatment using a pyrolysis furnace to decompose the residual organic resin binders on the surface of the sand particles, eliminating the potential for gas generation when reusing recycled sand, forming a complete closed loop for sand recycling, and significantly reducing the total amount of foundry solid waste emissions.

[0017] 3. The pyrolysis furnace in this application is designed with multiple temperature zones. The low-temperature hot air in the pyrolysis zone gently decomposes the resin binder on the surface of the sand particles, avoiding thermal shock pulverization of the sand particles. The oxygen-rich combustion in the oxidation zone thoroughly incinerates the carbonized residual organic matter. The high-temperature inert atmosphere in the sintering zone repairs the micro-cracks on the surface of the sand particles, so that the strength of the recycled sand meets the casting requirements of the key load-bearing areas of the casting.

[0018] 4. In this application, the hot air separated and purified by the air classifier is precisely introduced into the chamber between the first and second screens inside the screening shell through the second air duct. Through the directional release of the hot air flow in the target particle size sand particle aggregation area, the heat energy is mainly transferred to the target particle size sand particles to achieve deep preheating, while the coarse particles intercepted by the first screen and the fine powder discharged from the third outlet only receive a small amount of heat energy. When the preheated sand particles enter the subsequent pyrolysis furnace, the energy consumption required for heating the pyrolysis zone is greatly reduced, and the pyrolysis cycle is significantly shortened. At the same time, the hot air diffuses bidirectionally upward and downward from the middle, forming an airflow support on the upper first screen to prevent coarse particles from clogging the mesh, and forming a cyclone disturbance on the lower second screen to prevent fine sand from adhering, which significantly improves screening efficiency and heat energy utilization. Attached Figure Description

[0019] Figure 1 This is a flowchart of a sand casting process for a robot rotary table according to an embodiment of this application.

[0020] Figure 2This is an exploded view showing the sand mold assembly in the embodiments of this application.

[0021] Figure 3 This is a cross-sectional view illustrating sand mold #1 in the embodiments of this application.

[0022] Figure 4 This is a schematic diagram illustrating the structure of sand mold #3 in the embodiments of this application.

[0023] Figure 5 This is a schematic diagram illustrating the structure of sand mold #6 in the embodiments of this application.

[0024] Figure 6 This is a schematic diagram illustrating the overall structure of the sand recycling equipment in the embodiments of this application.

[0025] Figure 7 This is a cross-sectional view illustrating the internal structure of the screening machine in the embodiments of this application.

[0026] Figure 8 This is a cross-sectional view illustrating the internal structure of the pyrolysis furnace in the embodiments of this application.

[0027] Explanation of reference numerals in the attached drawings: 11. Sand mold #1; 111. Mounting hole; 112. Stop and limit edge; 12. Sand mold #2; 13. Sand mold #3; 131. Mounting groove; 14. Sand mold #4; 15. Sand mold #5; 16. Sand mold #6; 161. Block; 17. Sand mold #7; 18. Sand mold #8; 2. Sand mold crusher; 3. Screening machine; 31. Screening shell; 311. Feed inlet; 312. First discharge outlet; 313. Second discharge outlet; 314. Third discharge outlet; 32. First screen; 33. Second screen; 4. Pyrolysis furnace; 41. Cracking zone; 42. Oxidation zone; 43. Sintering zone; 5. Air classifier; 6. Cyclone separator; 61. First air duct; 7. Bag filter; 71. Second air duct. Detailed Implementation

[0028] The following combination Figures 1-8 This application will be described in further detail below.

[0029] Example:

[0030] This application discloses a sand casting process for a robot rotary table. (Refer to...) Figure 1 A sand casting process for a robot rotary table includes the following steps: S1, 3D printing sand mold design: Based on the three-dimensional data of the casting product, design the sand mold model of each sand mold component; S2. Sand mixing: Mix raw sand and recycled sand in a preset ratio to form mixed sand material; S3. Printing sand molds using 3D printing equipment: Using binder jetting technology, each sand mold is printed layer by layer using mixed sand material; S4. Sand mold treatment: Coat the surface of the sand mold with refractory coating and bake to cure; S5. Assembly: Assemble the sand mold components according to the assembly sequence; S6. Placing a pressure iron around the sand mold: Fill the outside of the sand mold with resin sand, and place a pressure iron on top of the sand mold after curing; S7. Casting: Melt the molten metal and pour it into the sand mold cavity. After cooling, the robot rotary casting is obtained.

[0031] This sand casting process uses 3D sand printing technology to print the sand mold components of the robot's rotating base. Compared with the traditional wooden mold split molding process, it completely eliminates the mold manufacturing process, ensuring high-precision molding of complex cavity structures and significantly improving the efficiency of sand mold production. In addition, by using recycled sand and raw sand in combination, it significantly reduces the consumption of raw sand and reduces the emission of foundry solid waste.

[0032] Reference Figure 1 and Figure 2 In step S1, the sand mold assembly includes 8 sand molds, namely: sand mold 1#, sand mold 2#, sand mold 3#, sand mold 4#, sand mold 5#, sand mold 6#, sand mold 7# and sand mold 8#. Among them, sand molds 1# to 6# form the outer contour system of the casting after assembly, and sand molds 7# and 8# form the gating system of the casting after assembly.

[0033] Reference Figure 3 The outer wall of sand mold 1# is provided with several mounting holes 111 that penetrate into the cavity. The mounting holes 111 are used to install the first chill. A stop limiting edge 112 is provided at one end of the mounting hole 111 near the cavity. The stop limiting edge 112 extends radially along the mounting hole 111 and covers part of the mounting hole 111. When the first chill is inserted into the mounting hole 111 from the outside of the sand mold 1#, its end face abuts against the stop limiting edge 112, thereby achieving axial positioning of the first chill and eliminating the positioning deviation of manual installation of the first chill. Meanwhile, the area not covered by the stop and limit edge 112 exposes the first chill to the cavity, forming a direct contact surface with the molten metal and establishing an efficient heat conduction path to ensure quenching efficiency.

[0034] Reference Figure 4 To further enhance the cooling effect, several mounting slots 131 for installing the second chill are provided on the side of sand mold #3 near the cavity.

[0035] Reference Figure 2 , Figure 3 and Figure 5The outer side of sand mold #6 is integrally printed with a plug 161 for sealing the remaining space outside the mounting hole 111. After the first chill is installed in sand mold #1, the plug 161 is pried off sand mold #6 and inserted from the outside of the mounting hole 111 until it is pressed against the first chill, thereby limiting the axial installation of the first chill. In addition, by sealing the mounting hole 111 with the plug 161, the risk of leakage of molten metal through the mounting hole 111 is avoided.

[0036] Reference Figure 1 and Figure 6 In step S2, recycled sand is prepared using sand recycling equipment, which includes a sand mold crusher 2, a screening machine 3, a pyrolysis furnace 4, and an air classifier 5 arranged sequentially. During centralized processing of waste sand molds, the sand mold crusher 2 mechanically dissociates the waste sand molds, converting the blocky sand molds into recyclable granular raw materials. The screening machine 3 classifies the crushed sand by particle size, accurately selecting sand particles of the target size. The pyrolysis furnace 4 treats the screened sand particles at high temperatures, decomposing the residual organic resin binder on the surface of the sand particles and eliminating the potential for gas generation during reuse of recycled sand. Since the pyrolyzed sand particles contain a small amount of carbon ash and dust, the air classifier 5 can purify the recycled sand through airflow filtration, ensuring the purity of the recycled sand and preventing micro-powder contamination that could lead to structural strength defects in the 3D sand mold printing process.

[0037] Reference Figure 6 and Figure 7 The sand crusher 2 is a jaw crusher. The screening machine 3 includes a screening shell 31 and a first screen 32 and a second screen 33 installed and fixed inside the screening shell 31. The first screen 32 is located above the second screen 33, and the mesh size of the first screen 32 is smaller than that of the second screen 33. The top of the screening shell 31 has a feed inlet 311 that communicates with the output port of the sand crusher 2 for receiving crushed sand. On one side of the screening shell 31, from top to bottom, there are a first discharge port 312, a second discharge port 313, and a third discharge port 314. The first discharge port 312 is located at the end of the first screen 32, the second discharge port 313 is located at the end of the second screen 33, and the third discharge port 314 is located at the bottom of the screening shell 31. Thus, the screening machine 3 adopts a double-layer screen structure. The upper first screen 32 intercepts large sand particles that are not fully crushed, while the lower second screen 33 accurately separates sand particles of the target size, ensuring that the particle size concentration of the recycled sand meets the passability requirements of the 3D printing equipment.

[0038] Reference Figure 8The pyrolysis furnace 4 is a horizontal pyrolysis furnace, which includes a cracking zone 41, an oxidation zone 42, and a sintering zone 43 arranged sequentially with progressively increasing temperatures. In the cracking zone 41, low-temperature hot air gently decomposes the resin binder on the sand grain surface, preventing thermal shock pulverization of the sand grains; in the oxidation zone 42, oxygen-enriched combustion thoroughly incinerates carbonized residual organic matter; and in the sintering zone 43, a high-temperature inert atmosphere repairs micro-cracks on the sand grain surface, ensuring that the strength of the recycled sand meets the casting requirements of critical load-bearing areas of the casting. In this embodiment, the temperature range set for the cracking zone 41 is 300–400℃; the temperature range set for the oxidation zone 42 is 600–650℃; and the temperature range set for the sintering zone 43 is 800–850℃.

[0039] Reference Figure 6 and Figure 7 The air outlet of the air classifier 5 is connected to a cyclone separator 6, the air outlet of the cyclone separator 6 is connected to a first air duct 61, the end of the first air duct 61 away from the air classifier 5 is connected to a bag filter 7, the air outlet of the bag filter 7 is connected to a second air duct 71, the air outlet of the second air duct 71 extends into the screening housing 31 and is located between the first screen 32 and the second screen 33. The hot air output from the air classifier 5 is purified by the cyclone separator 6 and the bag filter 7. It is then precisely introduced into the chamber between the first screen 32 and the second screen 33 inside the screening shell 31 through the second air duct 71. Through the directional release of hot air in the target particle size sand particle aggregation area, the heat energy is mainly transferred to the target particle size sand particles to achieve deep preheating. The coarse particles intercepted by the first screen 32 and the fine powder discharged from the third discharge port 314 only receive a small amount of heat energy. When the preheated sand particles enter the subsequent pyrolysis furnace 4, the energy consumption required for heating the pyrolysis zone 41 is greatly reduced, and the pyrolysis cycle is significantly shortened. At the same time, the hot air diffuses bidirectionally from the middle upward and downward, forming an airflow support for the upper first screen 32 to prevent coarse particles from clogging the mesh, and forming a cyclone disturbance for the lower second screen 33 to prevent fine sand from adhering, which significantly improves screening efficiency and heat energy utilization.

[0040] Reference Figures 1-5 Between steps S3 and S4, the first chill is installed into the mounting hole 111 of sand mold 1#, and the corresponding plug 161 is inserted into the mounting hole 111; the second chill is installed into the mounting groove 131 of sand mold 3#.

[0041] Reference Figure 1 and Figure 2 In step S4, paint should be applied to avoid paint buildup. After baking, a filter plate is placed in the flow channel of sand mold #7. The filter plate is made of ceramic material, which can intercept impurities in the molten metal and improve the casting quality.

[0042] Reference Figure 1 and Figure 2In step S5, the specific assembly sequence is as follows: First, attach sand mold #2 to sand mold #1, attach sand mold #3 to sand mold #2, and tighten with bolts; second, push sand mold #4 to sand mold #1 and tighten with bolts; finally, insert sand mold #5, sand mold #6, sand mold #7 and sand mold #8 in sequence to complete the assembly and seal, and tighten with bolts.

[0043] The implementation principle of the sand casting process for a robot rotary table in this application embodiment is as follows: The sand casting process uses 3D sand printing technology to print the sand mold components of the robot rotary table. Compared with the traditional wooden mold split molding process, it completely eliminates the mold manufacturing process, ensures high-precision molding of complex cavity structures, and greatly improves the efficiency of sand mold production. In addition, by using recycled sand and original sand in combination, the consumption of original sand is significantly reduced and the emission of foundry solid waste is reduced.

[0044] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A sand casting process for a robot rotary table, characterized in that, Includes the following steps: S1, 3D printing sand mold design: Based on the three-dimensional data of the casting product, design the sand mold model of each sand mold component; S2. Sand mixing: Mix raw sand and recycled sand in a preset ratio to form mixed sand material; S3. Printing sand molds using 3D printing equipment: Using binder jetting technology, each sand mold is printed layer by layer using mixed sand material; S4. Sand mold treatment: Coat the surface of the sand mold with refractory coating and bake to cure; S5. Assembly: Assemble the sand mold components according to the assembly sequence; S6. Placing a pressure iron around the sand mold: Fill the outside of the sand mold with resin sand, and place a pressure iron on top of the sand mold after curing; S7. Casting and molding; In step S2, the recycled sand is prepared by a sand recycling equipment, which includes a sand mold crusher (2), a screening machine (3), and a pyrolysis furnace (4) arranged in sequence. The screening machine (3) includes a screening shell (31) and a first screen (32) and a second screen (33) disposed in the screening shell (31). The first screen (32) is disposed above the second screen (33), and the mesh number of the first screen (32) is smaller than that of the second screen (33). The top of the screening shell (31) is provided with a feed inlet (311) for receiving crushed sand; a first discharge port (312), a second discharge port (313) and a third discharge port (314) are provided on one side of the screening shell (31) from top to bottom, wherein the first discharge port (312) is located at the end of the first screen (32), the second discharge port (313) is located at the end of the second screen (33), and the third discharge port (314) is located at the bottom of the screening shell (31); The sand recycling equipment also includes an air classifier (5) located after the pyrolysis furnace (4); the air outlet of the air classifier (5) is connected to a cyclone separator (6), the air outlet of the cyclone separator (6) is provided with a first air duct (61), the end of the first air duct (61) away from the air classifier (5) is provided with a bag filter (7), the air outlet of the bag filter (7) is connected to a second air duct (71), the air outlet of the second air duct (71) extends into the screening shell (31) and is located between the first screen (32) and the second screen (33).

2. The sand casting process for a robot rotary table according to claim 1, characterized in that: The pyrolysis furnace (4) is a horizontal pyrolysis furnace (4), which includes a cracking zone (41), an oxidation zone (42) and a sintering zone (43) arranged sequentially with progressively increasing temperatures.

3. The sand casting process for a robot rotary table according to claim 1, characterized in that, In step S1, the sand mold assembly includes 8 sand molds, namely: sand mold 1#, sand mold 2#, sand mold 3#, sand mold 4#, sand mold 5#, sand mold 6#, sand mold 7# and sand mold 8#. The outer wall of sand mold 1# is provided with several mounting holes (111) that penetrate into the mold cavity. The mounting holes (111) are used to install the first chill. The mounting hole (111) is provided with a stop limiting edge (112) at one end near the mold cavity. The stop limiting edge (112) extends radially along the mounting hole (111) and covers part of the mounting hole (111). When the first chill is inserted into the mounting hole (111) from the outside of the sand mold 1#, its end face abuts against the stop limiting edge (112) to achieve axial positioning of the first chill; Meanwhile, the area not covered by the stop limiting edge (112) exposes the first chill to the cavity, forming a direct contact surface with the molten metal to ensure the chilling efficiency.

4. The sand casting process for a robot rotary table according to claim 3, characterized in that: The outer side of sand mold #6 is provided with a plug (161) for sealing the remaining space outside the mounting hole (111).

5. The sand casting process for a robot rotary table according to claim 3, characterized in that: In step S4, after baking, place a filter sheet in the flow channel of sand mold #7.

6. The sand casting process for a robot rotary table according to claim 3, characterized in that: In step S5, firstly, sand mold #2 is attached to sand mold #1, and sand mold #3 is attached to sand mold #2, and then secured with bolts; secondly, sand mold #4 is pushed to sand mold #1 and secured with bolts; finally, sand mold #5, sand mold #6, sand mold #7 and sand mold #8 are inserted in sequence to complete the mold assembly and top sealing, and then secured with bolts.

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